Even Russia and North Korea have not completely abolished “elections,” they maintain a laughable facade of “democracy.” 0% chance of option 3. Option 2 is a given however. Hopefully it will “just” be Trump doing everything he can to put his thumb on the scale but not to an insurmountable degree, and not outright rigging to ensure his preferred candidate wins no matter what. But unfortunately the latter cannot be ruled out given who we're talking about here.
I think the latter can be ruled out since Trump and the GOP don't have full control over elections in any swing state.
What are the odds of option 1?
Oh but don’t you see? Trump will issue an executive order and/or demand Congress to deny the electors approved by the Democratic governors of any key states and instead accept “alternative electors” endorsed by Republicans. If Congress refuses, Trump will call on his supporters to coup the government again. Why not since he already did it once? And this time he might have prepared better to make sure at least part of the military and law enforcement is on his side too.
The odds of option 1 are the same as option 3. 0%. The idea that Trump wouldn’t at least try to rig the election is equally fantastical. It’s a question of degree and how successful he is, not whether he will try as that is guaranteed. Again, he already did it once. Nobody has any convincing argument for why he would not do it again.
How would Trump be able to rig a state-run election when he struggled mightily to do anything of note policy-wise at the federal level in his first term? Yes, he will probably try to rig it, but the chances are as close to zero as one can get that he’d be successful.